The present invention relates to a wire bonding method, a semiconductor device, a circuit board, an electronic instrument and a wire bonding device.
In the manufacture of a semiconductor device, wire bonding technology is applied in order to electrically connect the electrodes of a semiconductor chip to leads. In recent years, the pin-counts of semiconductor devices has been rising, but with conventional wire bonding technology, there are limits to wire lead-out, and therefore it has only been possible to support this by means of the form or layout of the electrodes of the semiconductor chip, or the form or construction of the leads.
The present invention solves this problem, and has as its objective the provision of a wire bonding method which allows a free lead-out of the wires, a semiconductor device manufactured by this method, a circuit board and electronic instrument provided with the semiconductor device, and a wire bonding device using this method.
(1) A wire bonding method of the present invention comprises:
a first step of disposing a plurality of leads aligned in an imaginary plane around the periphery of a semiconductor chip having a plurality of electrodes aligned on an imaginary straight line, such that the center-to-center spacing of the leads is greater than the center-to-center spacing of the electrodes;
a second step of bonding a wire to one of a pair formed by one of the electrodes and one of the leads;
a third step of bending the wire as viewed from a direction perpendicular to the imaginary plane; and
a fourth step of bonding the wire to the other of the pair of one of the electrodes and one of the leads.
According to the present invention, when the center-to-center spacing (pitch) is different for the electrodes and leads, by electrically connecting the two with wires, a pitch conversion can be carried out. Moreover, since the wire is bent, regardless of the electrode form or layout or the lead form or construction, the most effective wire lead-out is possible. For example, the wires can be drawn out so that the spacing between the wires is maximized.
(2) In this wire bonding method, the wire may be bent by using a pin in the third step.
By using a pin, the wire can be bent accurately.
(3) In this wire bonding method, the wire may be drawn out to a required length to connect one of the electrodes and one of the leads forming the pair, and then the wire may be bent, in the third step.
By means of this, since the wire drawn out to the required length is bent, the wire can be made stable and bent.
(4) In this wire bonding method, the wire may be drawn out to a length less than the distance between one of the electrodes and one of the leads forming the pair, and then while bending the wire, the wire may be further drawn out, in the third step.
By means of this, the wire of less than the required length can be drawn out while being bent.
(5) In this wire bonding method, the wire may be bonded to one of the electrodes in the second step; and the wire may be bonded to one of the leads in the fourth step.
By means of this, since the wire is first bonded to the electrodes, which have a smaller center-to-center spacing, the ease of operation is greater.
(6) In the third step of this wire bonding method, as viewed from a direction perpendicular to the imaginary plane, the wire may be drawn out from the electrodes in a direction parallel to an imaginary vertical line which perpendicularly intersects the imaginary straight line at the mid-point between a pair of electrodes at opposite ends of the aligned electrodes, and the wire may be bent in a direction away from the imaginary vertical line.
By means of this, the wires can be drawn out in a straight line from the electrodes, at a spacing substantially equal to the center-to-center spacing of the electrodes, and by bending the wire the pitch conversion can be carried out.
(7) In this wire bonding method, the first to fourth steps may be repeated in sequence from one of the electrodes closest to the mid-point, so that all of the plurality of electrodes and the plurality of leads are bonded.
By means of this, since the wire bonding is applied first to wires on the opposite side from the direction of bending, when moving the jig for bending the wire, the previously attached wires do not get in the way.
(8) In this wire bonding method, the wires may be bent on a second imaginary straight line.
By doing this, the wire spacing on the second imaginary straight line can be made substantially uniform.
(9) In this wire bonding method, the second imaginary straight line may intersect the imaginary straight line on which the electrodes are aligned, and the distance from one of the electrodes closest to the point of intersection to the second imaginary straight line may be less than the distance from the mid-point to the second imaginary line; and
an imaginary line connecting the extremities of the plurality of leads may extend on the side of the semiconductor chip from a third imaginary straight line which passes through the extremity of one of the leads closest to the imaginary vertical line and is parallel to the imaginary straight line on which the electrodes are aligned.
In this way, when the leads are aligned on an imaginary line meeting the above conditions, by bending the wires on the second imaginary straight line meeting the above conditions, the spacing of the wires can be increased.
(10) A semiconductor device of the present invention comprises:
a semiconductor chip having a plurality of electrodes aligned on an imaginary straight line;
a plurality of leads aligned in an imaginary plane around the periphery of the semiconductor chip, such that the center-to-center spacing of the leads is greater than the center-to-center spacing of the electrodes; and
a plurality of wires electrically connecting the electrodes and the leads, and bent as viewed from a direction perpendicular to the imaginary plane.
According to the present invention, when the center-to-center spacing (pitch) is different for the electrodes and leads, by electrically connecting the two with wires, a pitch conversion can be carried out. Moreover, since the wire is bent, regardless of the electrode form or layout or the lead form or construction, the most effective wire lead-out is possible. For example, the wires can be drawn out so that the spacing between the wires is maximized.
(11) In this semiconductor device,
as viewed from a direction perpendicular to the imaginary plane, the wires may be drawn out from the electrodes in a direction parallel to an imaginary vertical line which perpendicularly intersects the imaginary straight line at the mid-point between a pair of electrodes at opposite ends of the aligned electrodes, and the wires may be bent in a direction away from the imaginary vertical line.
By means of this, the wires can be drawn out in a straight line from the electrodes, at a spacing substantially equal to the center-to-center spacing of the electrodes, and by bending the wire the pitch conversion can be carried out.
(12) In this semiconductor device, the wires may be bent on a second imaginary straight line.
By doing this, the wire spacing on the second imaginary straight line can be made substantially uniform.
(13) In this semiconductor device,
the second imaginary straight line may intersect the imaginary straight line on which the electrodes are aligned, and the distance from one of the electrodes closest to the point of intersection to the second imaginary straight line may be less than the distance from the mid-point to the second imaginary straight line; and
an imaginary line connecting the extremities of the plurality of leads may extend on the side of the semiconductor chip from a third imaginary straight line which passes through the extremity of one of the leads closest to the imaginary vertical line and is parallel to the imaginary straight line on which the electrodes are aligned.
In this way, when the leads are aligned on an imaginary line meeting the above conditions, by bending the wires on the second imaginary straight line meeting the above conditions, the spacing of the wires can be increased.
(14) On a circuit board of the present invention, the above semiconductor device is mounted.
(15) An electronic instrument of the present invention is equipped with the above semiconductor device.
(16) A wire bonding device of the present invention comprises:
a table on which a semiconductor chip having a plurality of electrodes aligned on an imaginary straight line is mounted, and a plurality of leads aligned in an imaginary plane are disposed around the periphery of the semiconductor chip such that the center-to-center spacing of the leads is greater than the center-to-center spacing of the electrodes; and
a bonding tool for drawing out a wire and connecting the electrodes and the leads;
wherein the bonding tool moves between a pair formed by one of the electrodes and one of the leads, along a non-straight line as viewed from a direction perpendicular to the imaginary plane, and bends the wire.
According to the present invention, when the center-to-center spacing (pitch) is different for the electrodes and leads, by electrically connecting the two with wires, a pitch conversion can be carried out. Moreover, since the wire is bent, regardless of the electrode form or layout of the lead form or construction, the most effective wire lead-out is possible. For example, the wires can be drawn out so that the spacing between the wires is maximized.
(17) In this wire bonding device, the bonding tool may draw out the wire to a length required for connection of the pair formed by one of the electrodes and one of the leads, and then may bend the wire.
By means of this, since the wire drawn out to the required length is bent, the wire can be made stable and bent.
(18) In this wire bonding device, the bonding tool may draw out the wire to a length less than the distance between one of the electrodes and one of the leads forming the pair, and then while bending the wire, may further draw out the wire.
By means of this, the wire of less than the required length can be drawn out while being bent.
(19) In this wire bonding device, the bonding tool may bond the wire to one of the electrodes, and then bond the wire to one of the leads.
By means of this, since the wire is first bonded to the electrodes, which have a smaller center-to-center spacing, the ease of operation is greater.
(20) In this wire bonding device, as viewed from a direction perpendicular to the imaginary plane, the bonding tool may draw out the wire from the electrodes in a direction parallel to an imaginary vertical line which perpendicularly intersects the imaginary straight line at the mid-point between a pair of electrodes at opposite ends of the aligned electrodes, and may bend the wire in a direction away from the imaginary vertical line.
By means of this, the wires can be drawn out in a straight line from the electrodes, at a spacing substantially equal to the center-to-center spacing of the electrodes, and by bending the wire the pitch conversion can be carried out.
(21) This wire bonding device may further comprise a pin extending in a direction perpendicular to the imaginary plane and undergoing translational movement; and the bonding tool may contact the wire with the pin for bending.
By using a pin, the wire can be bent accurately.
(22) In this wire bonding device, the bonding tool may bond the wire to the electrodes in sequence from one of the electrodes closest to the mid-point.
By means of this, since the wire bonding is applied first to wires on the opposite side from the direction of bending, when moving the jig for bending the wire, the previously attached wires do not get in the way.
(23) In this wire bonding device, the bonding tool may bend the wire on a second imaginary straight line.
By doing this, the wire spacing on the second imaginary straight line can be made substantially uniform.
(24) In this wire bonding device, the second imaginary straight line may intersect the imaginary straight line on which the electrodes are aligned, and the distance from one of the electrodes closest to the point of intersection to the second imaginary straight line may be less than the distance from the mid-point to the second imaginary straight line; and
an imaginary line connecting the extremities of the plurality of leads may extend on the side of the semiconductor chip from a third imaginary straight line which passes through the extremity of one of the leads closest to the imaginary vertical line and is parallel to the imaginary straight line on which the electrodes are aligned.
In this way, when the leads are aligned on an imaginary line meeting the above conditions, by bending the wires on the second imaginary straight line meeting the above conditions, the spacing of the wires can be increased.
(25) This wire bonding device may further comprise a pin extending in a direction perpendicular to the imaginary plane and undergoing translational movement on the second imaginary straight line; and the bonding tool may contact the wire with the pin for bending.
By using a pin, the wire can be bent accurately.